Alexandre Oliva writes:

A program that requests __pthread_sig_debug to be blocked will
self-deadlock when it requests a thread to be created, because the
debugger (rda or gdb) will never get the signal, so it won't wake up
the pthread manager as expected.

This patch fixes it.

libpthread/linuxthreads/signals.c

@@ -38,9 +38,13 @@ int pthread_sigmask(int how, const sigset_t * newmask, sigset_t * oldmask)
     case SIG_SETMASK:
       sigaddset(&mask, __pthread_sig_restart);
       sigdelset(&mask, __pthread_sig_cancel);
+      if (__pthread_sig_debug > 0)
+	sigdelset(&mask, __pthread_sig_debug);
       break;
     case SIG_BLOCK:
       sigdelset(&mask, __pthread_sig_cancel);
+      if (__pthread_sig_debug > 0)
+	sigdelset(&mask, __pthread_sig_debug);
       break;
     case SIG_UNBLOCK:
       sigdelset(&mask, __pthread_sig_restart);